Switching tabs with the keyboard while using split-screen mode should wrap to the beginning of tabs for the split, not the entire window.

E.g., if I'm using a two-column layout, and I want to (in OS X) Command-} to go from the first tab to the last tab, I'd prefer that it wrap to the last tab of the split. In Beta 2183, Command-} wraps me to the last tab of the farthest-right column (the second column, in two-column layout).